The Cosmic Microwave Background? Not always…

The Universe isn’t a static place. Although the laws of nature (physics, chemistry, biology, etc.) don’t appear to change over time, everything in the Universe appears to evolve, and changes over time. One of the simplest ways that this happens is through Hubble expansion. General relativity tells us how the Universe expands, and more specifically, … Read moreThe Cosmic Microwave Background? Not always…

How to make a Black Hole

You and I have lived on planet Earth long enough to know that if you want to launch something into space, it needs to travel fast enough to escape the pull of Earth’s gravity. Launch it with too slow of a speed, and it crashes back into Earth. Launch it with a little more speed, … Read moreHow to make a Black Hole

Dark Matter: Is it right in front of us?

Last year, I had just finished my Ph.D. studies, and had moved to Madison, WI to teach introductory physics at the University of Wisconsin. I was working on this paper, and when I submitted it, I got a phone call from New Scientist magazine’s space division. Fast-forward two weeks, and I find this article online, … Read moreDark Matter: Is it right in front of us?

Centripetal vs. Centrifugal force, & the Solar System

One of the worst teaching tools physicists use (and they almost all do it) is to tell students, There’s no such thing as centrifugal force. What can you do when the top physics education website says, “It is important to note that the centrifugal force does not actually exist. We feel it, because we are … Read moreCentripetal vs. Centrifugal force, & the Solar System

An amazing discovery: a double Einstein Ring!

One of the perks of being a postdoc at a place like the University of Arizona, one of the top places in the US for astronomy, is that we get a number of really interesting visitors. Today we got paid a visit by Tommaso Treu, an astronomer at UC Santa Barbara. He spoke to us … Read moreAn amazing discovery: a double Einstein Ring!